Dental apparatus



Aug. 1952 c. A. ELLIS 3,050,855

DENTAL APPARATUS Filed May 10. 1957 2 Sheets-Sheet 1 INVENTOR. CHARLESA. ELLIS i MM.

A TTORIIEY 1962 c. A. ELLIS 3,050,855

DENTAL APPARATUS Filed May 10. 195'! 2 Sheets-Sheet 2 INVENTOR. GHARLESA. ELL/S ATTORNEY ilnite States 3,050,855 DENTAL APPARATUS Charles A.Ellis, Hamden, Conn., assignor to Ritter Company, Inc., Rochester, N.Y.,a corporation of Dela- Ware Filed May 10, 1957, Ser. No. 658,442 Claims.(CI. 32-26) the patient and enable the dentist to select the rate atwhich tooth material can be removed in accordance with the particularconditions under which the dentist is operating. For example, to quicklyremove a large amount of tooth material, as is desirable during theinitial stage of grinding or drilling, requires a relatively high speedof rotation of the drilling tool or burr; whereas for the subsequentdrilling stages, where usually only small amounts of tooth material areto be cut away, as in the finishing operation, the burr may be rotatedat a relatively lower speed. In the design of modern dental equipment,to provide a single handpiece driven over a speed range wide enough totake care of substantially all of the conditions under which the dentistmay be required to operate would involve a mechanism which iscomplicated, expensive, and inefiicient in operation. As far as isknown, the dental handpieces in use today are operable only within alimited speed range and thus do not perform satisfactorily where speedsoutside of this range could be used to more etfectively carry out aspecific operation.

In order to overcome the limitations of the limited speed range in asingle handpiece, two handpieces have been employed which are drivenover a difierent range of speeds so that each handpiece may beselectively used to obtain the particular operating speed within itsspeed range. However, it can readily be appreciated that in addition tothe cost of the two handpieces, a completely separate driving mechanismincluding a separate motor for each handpiece adds considerably to thecost of the complete unit and increases its size considerably. Thisobjectionable aspect has been partially overcome in some priorconstructions, where a single driving motor has been employed to driveboth of the handpieces. However, the driving connections between themotor and the handpieces was complicated'and diflicult to adjust.Furthermore, these previous constructions required a change in thedriving connections each time a change was made from one handpiece tothe other.

Accordingly, a primary object of this invention is to provide a newand'novel driving mechanism for dental handpieces.

Another object of this invention is to provide a new and novel drivingmechanism for a dental handpiece which is automatically connectedindriving engagement when the dental handpiece is moved from a stored toan operative position.

A further object of this invention is to provide a new and novel dentalhandpiece driving mechanism which permits selective operation of eitherof two dental handpieces driven over difierent speed ranges from asingle motor wherein the handpiece selected for use is automaticallyengaged with the driving mechanism.

A still further object of this invention is to provide a new andimproved driving'mechanism for dental handpieces which is simple andcompact in construction, easy Patented Aug. 28, 1962 to maintain,attractive in external appearance and which is capable of prolonged usewithout risk of breakdown.

This invention further contemplates a dual drive from a single motorarranged so that the dentist has two handpieces available capable ofbeing driven over a different range of speeds or, in the alternative,the dentist may use two handpieces of different types, one, for example,a straight angle and the other a contra angle handpiece, the drive beingarranged so that the handpiece selected for use is automaticallyconnected to the motor upon drawing the handpiece toward the position ofwork and disconnection of the drive from the motor is automaticallyeffected upon restoring the handpiece to its position of non-use.

Other objects and advantages of this invention will be particularly setforth in the claims and will be apparent from the following description,when taken in connection with the accompanying drawings, in which:

FIG. 1 is a partial elevation view of dental apparatus incorporating thenovel driving mechanism of the invention;

FIG. 2 is a partial plan View of the dental apparatus of FIG. 1;

FIG. 3 is an enlarged sectional view, broken away, taken substantiallyalong line 33 of FIG. 1 in the direction of the arrows; and

FIG. 4 is a sectional view taken substantially along line 44 of FIG. 3in the direction of the arrows.

As is well known in the practice of dentistry, it is highly desirable intooth drilling and similar tooth cutting operations that the dentalhandpiece, containing the dental cutting tool, be driven at a selectedspeed which is governed, in general, by the amount of toot'material tobe removed. In general, the greater the amount of tooth material to beremoved, the greater the speed required. A variable speed within asingle limited range has been obtained in previous constructions by theuse of a foot pedal actuated rheostat or the like. However, it has beenfound in practice, that two widely separated speed ranges are mostdesirable to take care of most operating conditions encountered whichcan, for convenience, be identified as a high and low speed range. Thisdual range is best accomplished by the use of two handpieces and it isthe purpose of this invention to provide a unitary driving mechanism fortwo such handpieces.

Referring now to FIG. 1, a support stand of any suitable type isprovided which is designated generally by the numeral 1 1 and on whichis supported a pair of dental handpiece assemblies, designated generallyby the numerals 12, 13.

In accordance with the arrangement of the invention, handpieces 14 areprovided on both of the handpiece assemblies 12, 13 and as bothassemblies are similar in construction, a portion of assembly 13including the handpiece has been omitted for clarity and only assembly12 will be described in detail. The handpiece 14 is shown as a contraangle type but it should be understood that any suitable type ofhandpiece may be employed.

In the illustrated embodiment, handpiece 14 is preferably arranged to bedriven in the high range (preferably 40,000 rpm. and up) while thehandpiece of as sembly 13 is driven in the low range (preferably 2,000to 8,000 r.p.m.). It should be understood that these speed ranges areillustrative only and that the scope of the invention includes drivingeach of the handpieces through any desired speed range. Furthermore, itshould be understood that the motor is provided in the conventionalmanner with speed control means such as a foot pedal by which the speedof each handpiece may and boom 19 pivotally connected by suitable meansat 20, 21 and arranged to support a handpiece driving belt 22. 16 maybeof any conventional construction such as commonly used today in dentalapparatus of the type described. e

A handpiece driving motor, designated generally by V the numeral 23, issuitably mounted on the support stand 11 and is provided with a frame24and a shaft 26 having opposite ends projecting outwardly from the frame24 as shown in FIG. 3.

The folding bracket 16 is mounted at each end of the motor 23 by meansof an annular member or support ring 27 suitably attached to one end ofthe boom 19 and offset from the axis of the boom at 25 as shown in FIGS.2, 3. The ring 27 is rotatably mounted on a sleeve 28 having a portion30 of reduced diameter. Each end of the motor frame 24 is provided witha sleeve 28, preferably integral therewith, through which the motorshaft 26 extends. The ring 27 may therefore rotate on sleeve 28 to pivotthe boom 19 and additionally, may sliderelative to the sleeve in amanner to be more fully explained hereinafter.

In order to drive the handpieces 14 carried by the assemblies 12, 13,the driving belts 22 extend around pulleys 29, 31 freely mounted forsliding movement and rotation by means suchas roller bearings 32 on asleeve portion 30 adjacent each end of motor shaft 26 as shown in FIG.3. It will be noted that the offsetting of the ring 27 at 2'5 preventsinterference of the belt 22'with its associated pulley. The pulleys 29,31 are provided with peripheral grooves 33, 34, respectively, forreceiving the belts 22. Each of the pulley grooves 33, 34 is of aselected depth or effective diameterto drive its associated belt at apredetermined speed. It will be noted that pulley groove 33 is shallowerthan pulley groove 34 so that the handpiece assembly-12 carries the highspeed handpiece 14. The handpiece assembly 13 therefore carries the lowspeed handpiece.

shaft 26 comprising a clutch plate 39 carrying a friction disc or washer41 fixed to its inner face. The clutch plate is suitably fixed to theshaft 26 by means such as.

pin 40. Movement of either of the pulleys 29, 31 axially outward intoengagement with its associated clutch means or disc 41 when the motorshaft 26 is rotating, will result in a rotation of the pulley by theplate and drive the associated handpiece through the belt 22.

Means have been provided .to guide the movement of each ring 27 and toresiliently retain the ring against the motor frame 24 with itsassociated pulley out of engagement with the clutch disc 41 from themotor and more specifically, the ring 27 is provided with a plurality ofarcuate slots 42 as shown best in FIG. 4. In the illus tratedembodiment, there has been shown four of such arcuate slots 42, radiallyspaced on the ring and each provided with 'a portion of reduced width 43forming a shoulder 44.

A guide stud 46 having a head 47 is positioned within each of the slots42 and is threadedly engaged within a corresponding threaded opening 48in the motor frame 24 as shown in FIG. 3. A spring 49 is positionedaround the shank of stud 46 so as to lie between the bolt head 47 and awasher 50 which seats on the slotrshoulder 44.

In this manner, the boom ring 27 is resiliently held.

against the motor frame 24 with its associated pulley disengaged fromthe clutch disc '41, but is arranged to be moved axially outward alongthe frame sleeve 28 against the biasing action of springs 49. 1

In order to slide the ring 27 axially outward and con- It should beunderstood that the folding brackets sequently move its associatedpulley intohandpiece driv-' ing engagement with friction disc 41, thering contains cam means such as a cam or projection 51 on the outer edgeof its inner face as shown best in FIG. 2. 7 The cam V 51 is arranged toseat in a correspondingly shaped depression. or recess 52 preferablypositioned on the motor 7 frame. When the ring 27 is held in engagementwith the motor frame by the spring 49 and its associated pul-' ley isdisengaged from the clutch disc 41, the cam 51 will seat fully in therecess 52.

It can thus be seen that when the boom 19 is rotated together with thering 27, the ring is cammed axially outward by the rising of cam 51 onthe higher surface ofthe motor frame relative tothe recess 52against'thebiasing action of springs 49. This outward movement bly 12 isshown in the stored or non-use position with the boom 19 pivotedupwardly to engage the ring cam 51 in recess 52. The handpiece 14 may behung for convenience on a bracket 53 supported on the folding bracketrod 18. 'The pulley 29 has been moved toward the motor frame away fromits associated clutch disc 41 the pulley. I

Either of the handpiece assemblies 12, 13 may be rotated from the storedposition illustrated by assembly 12 in FIG. 1 downwardly into theposition shown occupied by the handpiece assembly 13. The pulley is'thusdrivably engaged as in the case of pulley 3-1 in FIG. 3 and thehandpiece 14 may-now be operated by the dentist under the limited speedcontrol permitted by the associated'foot pedal (not shown). Aspreviously explained, the thrust bearing 36 permits substantially.frictionless rotation between the inner face of the pulley and the outerface of the boom ring 17. 7

'It can thus be seen that a single motor has been pro-I vided in whichthe motor shaft drives a dental handpiece I connected at each endthereof. By merely pivoting one of the handpieces' downwardly from astored position,

the handpiece drive is connected automatically tov the rotating motorshaft so that the dentist need only use a foot .pedal control forcontrolling the speed overthe predetermined range leaving his hands freeand greatly simplifyingthe speedchatngingoperation. 'It will also benoted that different speed ranges are easily established for eachhandpiece as the size of the pulley determines the speed in which thehandpiece is driven. Although such an occasion would be rare, bothhandpieces could 55 be driven at the same time.

The important aspects of this invention are that no manually operatedclutch or clutches are required. The

dentist automatically connects the drive of the handpiece having therange he desires to use during the act of moving the handpiece to theoperative position. Correspond- 1 the invention is to provide pulleys ofthe same diameter or different diameters as shown and use two handpiecesof different construction, for example, a straight angle handpiece and acontra angle handpiece. While there has been shown and described thepreferred forms of mechanisms of the invention, it be apparent thatvarious changes and modifications maybe made therein, particularly inthe form and relation of parts, without departing from the spirit of theinvention as set forth in the appended claims.

so that the motor shaft 26 may be rotated without driving 1 I claim:

1. Dental apparatus comprising, in combination, a dental handpieceassembly including a handpiece, a driving motor, means supporting saidhandpiece for swinging movement with respect to said motor, and drivingmeans partially carried by said supporting means mechanicallyinterconnecting said motor and said handpiece, said supporting meansbeing arranged to move between a position wherein said handpiece ismechanically disengaged from said driving motor to a position drivablyinterconnecting said handpiece with said driving motor.

2. Dental apparatus comprising, in combination, a dental handpieceassembly including a handpiece, a driving motor having a shaft fordriving said handpiece, means supporting said handpiece for swingingmovement with respect to said motor between a driving position and astored position and driving means including a clutch drivably connectingsaid motor shaft to said handpiece, said supporting means being arrangedto engage said clutch and connect said driving motor to said handpiecewhen it is swung from a stored position to a driving position.

3. Dental apparatus comprising, in combination, a driving motor having ashaft, a dental handpiece assembly including a handpiece and a boomsupporting said handpiece for swinging movement relative to said motorshaft, driving means including a clutch drivably connecting said motorshaft to said handpiece, and cam means on said boom being arranged toengage said clutch and connect said driving means to said handpiece whenit is swung from a stored position to a driving position.

4. Dental apparatus comprising, in combination, a driving motor having aframe and a driving shaft, a dental handpiece assembly including ahandpiece and a boom for supporting said handpiece for swinging movementrelative to said shaft between a stored position and a driving position,said boom having a support ring arranged to pivot and slide axially ofsaid shaft, driving means drivably connecting said shaft to saidhandpiece including a clutch plate on said shaft, a normally disengagedpulley slidably mounted on said shaft, and belt means connecting saidpulley to said handpiece, cam

means on said boom being arranged to slide said boom and engage saidpulley with said plate when said handpiece is swung from a storedposition to a driving position.

5. Dental apparatus in accordance with claim 4 wherein said cam meanscomprise a cooperating projection and depression arranged on said motorframe and boom ring for relative axial movement, and including meansbiasing said boom for axial movement in a direction whereby saidprojection is seated within said depression.

6. Dental apparatus in accordance with claim 4 wherein said pulley isconnected to said boom support ring for axial movement therewith andsaid boom is provided with an offset maintaining said belt means inproper alignment with said pulley.

7. A dental drilling unit adapted to be controlled by a single motorcontroller comprising, in combination, a motor the range of speed ofwhich is controlled by said motor controller, pulleys of differentdiameters mounted on opposite sides of said motor, means including apair of clutches operatively connecting either of said pulleys to themotor, a pair of handpieces, means driving one of said handpieces fromone of said pulleys, means driving the other of said handpieces from theother of said pulleys, a pivoted support for each of said handpieces andits driving means, each of said pivoted supports having a drivingposition and a stored position and means automatically engaging theclutch of the handpiece selected for use when the corresponding supportis moved from its stored position to its operating position anddisconnecting said clutch automatically when the support is returned toits stored position.

8. A dental drilling unit in accordance with claim 7 wherein said clutchof the selected handpiece is automatically disengaged when the supportis returned to its stored inactive position and said automatic clutchengaging means includes means enabling a range of pivotal movement ofsaid support with the support in its active position without disengagingsaid clutch.

9. Dental apparatus comprising, in combination, a motor, a support forsaid dental hand piece, a driving connection between said motor and saidhand piece, means permitting said support to be shifted from a storedinactive position to a hand piece driving active position and meansautomatically mechanically engaging said driving connection with themotor when said support is shifted from the inactive position to theactive position.

10. Dental apparatus in accordance with claim 9 in which the support ispivoted and clutch elements are carried by the support and by the motorwhich elements are engaged when the support is moved to its active position. 'il

Hanson Oct. 29, 1907 Neel Nov. 30, 1920

